Hi Peter, > I wrote a litte C++ demo which shows that the error occurs in v4.31 (and > previous versions), but not in v4.33. The same happens with the > executables (glpsol.exe).
> Maybe this information is useful for you. > But anyway, since the latest version behaves nicely, everything is OK! I tested your demo model with glpk 4.31. In fact, the results were incorrect. In the changelog I found the following record concerning glpk 4.32: * glpmpl01.c A bug was fixed. Due to this bug iterated expressions having an indexing expression whose dummy indices are bound to some values, i.e. like sum{(i+1,j,k-1) in E} x[i,j,k] are evaluated incorrectly. Namely, current value of such expressions is not invalidated when corresponding dummy indices (like i and k in the example above) are changed, that erroneously results in the same value evaluated for the first time. Most probably this bug (which now is fixed) caused incorrect results. BTW, I noticed that in your code you are using routines _glp_lpx_read_model and _glp_lpx_write_mps; this is not a good idea, because these symbols may disappear in further versions of the package. Please use documented api routines glp_mpl_... and glp_write_mps instead. Best regards, Andrew Makhorin _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org http://lists.gnu.org/mailman/listinfo/help-glpk